The present invention relates to a monolever operation apparatus for a working vehicle such as a bulldozer, and particularly relates to a monolever operation apparatus for a working vehicle, in which forward and reverse gearshift of a transmission, and a left and right steering operation of the working vehicle are performed by operating a monolever in four of fore-and-aft, and left and right directions, and the monolever is provided with a palm rest for supporting a palm.
In working vehicles such as a bulldozer, a hydraulic type excavator and a mobile crane, operations are normally performed efficiently by simultaneously operating the working machine while driving a vehicle. For this purpose, an operating lever apparatus, which can easily operate a vehicle and a working machine at the same time, and which can perform the driving operations with stability against vibrations of the vehicle during traveling, have been conventionally developed, and as one measure, a monolever operation apparatus is often adopted.
FIG. 16A and FIG. 16B are views for explaining one example of typical monolever operation apparatus (for example, Japanese Utility Model Laid-open No. 6-33218) which is conventionally used in a bulldozer (hereinafter called a working vehicle), and show an explanatory plane view and a sectional side view of the monolever operation apparatus. The explanation will be made below based on FIG. 16A and FIG. 16B.
A monolever 95 is vertically provided at a rotary shaft 96 for rotating the monolever 95 in a fore-and-aft direction. The monolever 95 is rotatable in a left and right direction (the direction orthogonal to the paper surface in FIG. 16A). By the rotation in the left and right direction, each clutch and brake of each steering device (not illustrated) for controlling the left and right steering directions of the traveling equipment of a vehicle can be engaged and disengaged via a known link mechanism not illustrated. The monolever 95 is also rotatable in a fore-and-aft direction (the left and right direction of the paper surface in FIG. 16A). By the rotation in the fore-and-aft direction, forward and reverse clutches of a transmission can be engaged and disengaged via a link 97, and any one of speed gear clutches, for example, from a fist speed to a third speed, of the transmission can be engaged via a link 98.
As shown in FIG. 16A and FIG. 16B, by operating the monolever 95 from the neutral position to the forward position, a forward first speed gear (F1), a forward second speed gear (F2) and a forward third speed gear (F3) can be operated in succession. By operating the monolever 95 from the neutral position to the reverse position, a reverse first speed gear (R1), a reverse second speed gear (R2), and a reverse third speed gear (R3) are operated in succession. An operator places a portion of his or her arm below the elbow on an arm rest 90, and operates the monolever 95 in the fore-and-aft, and the left and right directions with the portion below the elbow as a fulcrum of operation P. It should be noted that an axis of rotation H0 in the left and right direction of the monolever 95 is placed horizontally in the fore-and-aft direction.
The monolever 95 as described above is operated in the left and right direction relative to a traveling direction of the working vehicle, thereby engaging the clutch with corresponding one of the left and right steering devices of the vehicle, and applying the brakes on the other one thereof to thereby enabling the vehicle to turn to the left or the right. Further, the monolever 95 is operated in the fore-and-aft direction relative to the traveling direction of the working vehicle, thereby making it possible to shifting the speed gears of the transmission.
The conventional monolever operation apparatus as described above, however, has the following disadvantages.
In the conventional monolever operation apparatus shown in FIG. 16A and FIG. 16B, the fulcrum of operation (below the elbow) P in a situation in which the elbow of the operator is placed on the arm rest 90 is at the position upper than the axis of rotation HO of the rotational operation of the monolever 95. Due to this placement, when the vehicle is turned to the left or the right, a distance between P and B, which is from the fulcrum of operation P to a left turn stroke end position B, and a distance between P and C, which is from the fulcrum of operation P to a right turn stroke end position C, change relative to a distance between P and A from the fulcrum of operation P to a center point A (hereinafter, called the neutral position A) of the grip operation in the neutral position of the monolever 95. Consequently, the operator needs to displace the fulcrum of operation P below the elbow when performing turning operations. Accordingly, the operation of the monolever 95 of the working vehicle for performing construction work lacks accuracy, thereby causing the disadvantage that a fine operation cannot be performed.
Further, since the grip of the monolever 95 is almost a cylindrical shape in a vertical direction, if the gripping force reduces during long hours of operation, the hand sometimes slips downward, therefore making it necessary for the operator to grip it once again, which causes the disadvantage of inconvenience in operation.
The turning of the hand is large at the maximum stroke position in the left and right direction of the monolever 95 which is operated with the operator""s elbow being placed on the top surface of the arm rest 90, and especially at the maximum stroke position to the outer side of the operator""s seat, the palm faces upward, which reduces operability, thus causing a great deal of fatigue after long hours of operation.
In view of the above conventional disadvantages, an object of the present invention is to provide a monolever operation apparatus for a working vehicle, which carries out the operations for traveling such as steering, and forward and reverse gearshift of a working vehicle by means of a monolever with excellent fine operability, with less fatigue being caused during long hours of operation, and with improved operability.
In order to attain the above object, a monolever operation apparatus for a working vehicle according to the present invention is a monolever operation apparatus for a working vehicle including an arm rest provided at a console placed at least any one of the left and right sides of an operator""s seat, and a monolever placed in front of the arm rest and rotatively operated in a fore-and-aft direction and a left and right direction respectively, and is characterized in that when operated in the left and right direction, the monolever is allowed to be operated with a distance from a fulcrum of operation below an operator""s elbow placed on the arm rest to a grip of the monolever being almost constant.
According to the above configuration, when the monolever is operated in the left and right direction, the distance from the fulcrum of operation below the operator""s elbow to the grip of the monolever is almost constant, and therefore the fulcrum of operation below the elbow is not displaced even when the monolever is operated in the left and right direction. As a result, the fulcrum of operation is fixed and the arm does not swing, therefore improving operability. Further, fine operability is improved, and less fatigue is caused even after long hours of operation, thus improving workability.
Further, an axis of a first rotary shaft for rotating the monolever in the left and right direction may pass through the vicinity of the fulcrum of operation.
According to the above configuration, the axis of the rotary shaft in the left and right direction passes through the fulcrum of operation below the operator""s elbow placed on the arm rest. As a result, the locus of the line connecting the fulcrum of operation and the grip becomes a cone surface with the fulcrum of operation as its vertex. Accordingly, the distance from the fulcrum of operation to the grip becomes constant, and thus the fulcrum of operation is not displaced during the operation in the left and right direction. As a result, the fulcrum of operation is fixed, and the arm does not swing, therefore improving operability. Further, fine operability is improved, and less fatigue is caused even after long hours of operation, thus improving workability.
Furthermore, a side wall, which is raised upward and formed to extend at least from a position, on which the elbow is placed, toward the front, may be provided on the outer side portion of the top surface of the arm rest.
According to the above configuration, at least the operator""s elbow is fixed at the side wall, thereby making it possible to securely operate the monolever with stability even with the vibrations of the vehicle. Further, the side wall is preferably provided throughout a predetermined length from the elbow to the front portion (forearm), thereby further increasing the stability of the arm.
Further, the top surface of the arm rest may be inclined at a predetermined angle from the vicinity of the position, at which the operator""s elbow is placed, toward the front.
According to the above configuration, when operating the monolever, the underside surface of the forearm in front of the operator""s elbow doesn""t touch the arm rest, therefore improving operability. Especially, in a fine operation, operability is improved.
Furthermore, the monolever may have a palm rest for supporting the palm formed integrally at the lower portion of the grip, and
in the neutral position, the upper end of the grip may be inclined at a predetermined angle so that the inner side of the grip is positioned in front of the outer side thereof relative to the left and right direction, and is inclined toward the operator side at about 30 degrees to about 45 degrees relative to the horizontal surface.
According to the above configuration, the lower portion of the palm grasping the grip is placed on the palm rest, thereby making it suitable for the operator to only grasp the grip lightly. Accordingly, the surface pressure exerted on the hand is reduced to be low, therefore reducing the load exerted on the operator. Further, in the neutral position, the upper end of the grip is inclined at the predetermined angle (for example, about 8 degrees) so that the inner side of the grip is forward of the outer side thereof relative to the left and right direction, and is inclined at about 30 degrees to about 45 degrees toward the operator side relative to the horizontal surface, and therefore the hand grasping the grip is in a natural position. Consequently, the operator can operate the monolever in a comfortable position without undue stress, therefore reducing fatigue, and improving operability and workability.
Further, an angle made by a line of the palm and the horizontal surface when the monolever is operated to the maximum stroke outward in the left and right direction may be not more than about 90 degrees, and
an angle made by a line of the palm and the horizontal surface when the monolever is operated to the maximum stroke inward in the left and right direction may be not less than about 0 degrees.
According to the above configuration, the turning of the palm to the inner side or the outer side does not become large even if the monolever is operated to the maximum stroke end to the inner side and the outer side in the left and right direction, therefore making it possible to perform the operations in a comfortable position and increase operability.
The monolever operation apparatus may further include a first rotary shaft for rotating the monolever in the left and right direction, and
a second rotary shaft which is placed at a position lower than the first rotary shaft and rotates the monolever in the fore-and-aft direction, and
the maximum stroke of the monolever in the fore-and-aft direction may be smaller than the maximum stroke thereof in the left and right direction.
According to the above configuration, the rotary shaft in the fore-and-aft direction is placed at a position lower than the rotary shaft in the left and right direction, therefore making the turning radius in the fore-and-aft direction larger than that in the left and right direction. In addition, the maximum stroke in the fore-and-aft direction is made smaller than that in the left and right direction, and therefore the vertical movement of the grip turning in the fore-and-aft direction reduces more compared to that of the grip turning in the left and right direction, and the grip turning in the fore-and-aft direction moves linearly. Accordingly, the operation of shifting the forward and reverse gears is facilitated. Further, as described above, the maximum stroke in the fore-and-aft direction is made smaller than that in the left and right direction, and therefore the position of the grip is not displaced from the neutral position to a large extent even if the monolever is operated in the fore-and-aft direction, which does not make a great change in the relationship between the axis of the rotary shaft in the left and right direction during the operation in the left and right direction, and the fulcrum of operation below the elbow. As a result, even if the operation in the left and right direction is performed at the maximum stroke position in the fore-and-aft direction, the locus of rotation of the grip in the left and right direction draws a circular arc of the bottom surface of the cone with the fulcrum of operation as its vertex, and therefore the fulcrum of operation is not displaced. Accordingly, the monolever can be operated with stability.
Furthermore, a recessed portion may be formed along the fore-and-aft direction on the outer side portion of the console.
According to the above configuration, with the thumb being placed on the grip, or with the thumb, index finger, middle finger or the like gripping the grip, the rest of the fingers (for example, four fingers other than the thumb, or three fingers or less) are rested in the recessed portion, thereby fixing the finger tips to facilitate to adjust the manipulated variable by the finger tips, and improving fine operability. Further, the entire forearm from the elbow to the hand can be fixed, therefore making it possible to securely perform the operations with the operator""s body being stabilized even if vibrations are caused in the working vehicle.
Furthermore, the recessed portion may be formed throughout the range of the maximum stroke during a forward and reverse gear shifting operation of the monolever.
According to the above configuration, throughout the range of the maximum stroke when the monolever is operated to shift the forward and reverse gears, with the thumb, or the thumb and the other fingers being placed on the monolever, the finger tips can be fixed by placing the rest of the fingers in the recessed portion. Accordingly, in any position in which the forward and reverse gears are shifted, workability and fine operability can be improved, and the operator""s body can be always stabilized during the operation of the working vehicle.
A method for operating a monolever operation apparatus for a working vehicle according to the present invention is a method for operating a monolever operation apparatus for a working vehicle in which a monolever placed in front of an arm rest provided at a console placed at any one of the left and right sides of an operator""s seat is rotatively operated in a fore-and-aft direction and a left and right direction respectively, and is characterized by including the steps of:
placing an operator""s elbow on the top surface of the arm rest and pressing the operator""s forearm against and along a side wall provided on the outer side of the top surface of the arm rest,
while placing the elbow thereon and pressing the forearm against the side wall, griping a grip with the palm facing diagonally downward to the operator""s seat side and with the operator""s seat side of the grip of the monolever being positioned in front of the outer side of the grip, and
performing at least one of the following:
on shifting forward and reverse gears, rotating the monolever in the fore-and-aft direction;
on steering the vehicle, rotating the monolever in the left and right direction from the inward maximum stroke position to the outward maximum stroke position with an angle made by a line of the palm and the horizontal surface ranging from about 0 degrees to about 90 degrees, and with the distance from a fulcrum of operation below the operator""s elbow to the grip always remaining almost constant; and
on shifting speed gears of a transmission, performing a speed change operation by operating a speed gear shifting switch placed at the foremost end portion of the grip with a thumb.
According to the above configuration, since the forearm is pressed against and along the side wall provided on the outer side of the top surface of the arm rest, the forearm is stabilized against the vibrations, thereby improving operability. Since the grip is grasped with the palm facing diagonally downward to the operator""s seat side, and with the operator""s seat side (inner side) of the grip being in front of the outer side of the grip, the palm grasping the grip is in a natural position, thus making it possible to perform operation in a comfortable position. Further, during the steering operation of the vehicle, even if the monolever is operated from the inner side maximum stroke position to the outer side maximum stroke position in the left and right direction, the palm is turned in the range from about 0 degrees to about 90 degrees, and thus the palm is not turned to a large extent. Accordingly, the operation in the left and right direction can be easily performed. Further, since the monolever is turned in the left and right direction with the distance from the fulcrum of operation below the operator""s elbow to the grip being almost constant at all times, the fulcrum of operation is never displaced, thereby stabilizing the forearm, and improving operability and workability. When the speed gear switch is provided at the foremost end portion of the grip, the speed gears can be easily shifted at the same time that the forward and reverse gearshift and steering operation are performed.
Further, when performing a fine operation while steering the vehicle, any fingers other than the thumb may be rested on a recessed portion provided along the fore-and-aft direction on the outer side portion of the console, and the grip may be gripped with at least the thumb to perform the operation.
According to the above configuration, when a fine operation is performed, any fingers other than the thumb are placed in the recessed portion provided on the outer side portion of the console along the fore-and-aft direction, and the grip is grasped at least by the thumb, or the thumb and the other fingers to carry out the operation. As a result, the finger tips are fixed, therefore making it possible to improve fine operability and reduce the swings of the operator""s finger tips and body when vibrations are caused.